/**
 * ***************************************************************************** Copyright (c) 2000,
 * 2007 IBM Corporation and others. All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: IBM Corporation - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.jface.viewers;

import java.util.Iterator;
import java.util.List;

/** A selection containing elements. */
public interface IStructuredSelection extends ISelection {
  /**
   * Returns the first element in this selection, or <code>null</code> if the selection is empty.
   *
   * @return an element, or <code>null</code> if none
   */
  public Object getFirstElement();

  /**
   * Returns an iterator over the elements of this selection.
   *
   * @return an iterator over the selected elements
   */
  public Iterator iterator();

  /**
   * Returns the number of elements selected in this selection.
   *
   * @return the number of elements selected
   */
  public int size();

  /**
   * Returns the elements in this selection as an array.
   *
   * @return the selected elements as an array
   */
  public Object[] toArray();

  /**
   * Returns the elements in this selection as a <code>List</code>. <strong>Note</strong> In the
   * default implementation of {@link #toList()} in {@link StructuredSelection} the returned list is
   * not a copy of the elements of the receiver and modifying it will modify the contents of the
   * selection.
   *
   * @return the selected elements as a list
   */
  public List toList();
}
